Prayer, other than the Mass, is not a ‘ritual’. It is simply communication with God or with a saint, as one would communicate with a parent or a trusted friend.
If you want to pray to St Peter, pray to him - simply use your own words, or a written prayer if you prefer, but it is most important to mean what you say. Please don’t fall into the trap of thinking there is any one ‘right’ way to do it, or that things like candles or crossed keys are required.
That smacks of superstition, as if prayer were a magical incantation or spell or something.